DATAJDBC-165 - Allows configuration of custom RowMapper on @Query annotation.

src/main/java/org/springframework/data/jdbc/repository/query/Query.java

@@ -22,6 +22,7 @@ import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
 import org.springframework.data.annotation.QueryAnnotation;
+import org.springframework.jdbc.core.RowMapper;
 
 /**
  * Annotation to provide SQL statements that will get used for executing the method.
@@ -36,5 +37,14 @@ import org.springframework.data.annotation.QueryAnnotation;
 @QueryAnnotation
 @Documented
 public @interface Query {
+
+	/**
+	 * The SQL statement to execute when the annotated method gets invoked.
+	 */
 	String value();
+
+	/**
+	 * Optional {@link RowMapper} to use to convert the result of the query to domain class instances.
+	 */
+	Class<? extends RowMapper> rowMapperClass() default RowMapper.class;
 }

src/main/java/org/springframework/data/jdbc/repository/support/JdbcQueryMethod.java

@@ -28,9 +28,7 @@ import org.springframework.lang.Nullable;
 
 /**
  * {@link QueryMethod} implementation that implements a method by executing the query from a {@link Query} annotation on
- * that method.
- *
- * Binds method arguments to named parameters in the SQL statement.
+ * that method. Binds method arguments to named parameters in the SQL statement.
  *
  * @author Jens Schauder
  * @author Kazuki Shimizu
@@ -40,6 +38,7 @@ public class JdbcQueryMethod extends QueryMethod {
 	private final Method method;
 
 	public JdbcQueryMethod(Method method, RepositoryMetadata metadata, ProjectionFactory factory) {
+
 		super(method, metadata, factory);
 
 		this.method = method;
@@ -52,12 +51,18 @@ public class JdbcQueryMethod extends QueryMethod {
 	 */
 	@Nullable
 	public String getAnnotatedQuery() {
-
-		Query queryAnnotation = AnnotatedElementUtils.findMergedAnnotation(method, Query.class);
-
-		return queryAnnotation == null ? null : queryAnnotation.value();
+		return getMergedAnnotationAttribute("value");
 	}
-	
+
+	/**
+	 * Returns the class to be used as {@link org.springframework.jdbc.core.RowMapper}
+	 *
+	 * @return May be {@code null}.
+	 */
+	public Class<?> getRowMapperClass() {
+		return getMergedAnnotationAttribute("rowMapperClass");
+	}
+
 	/**
 	 * Returns whether the query method is a modifying one.
 	 *
@@ -68,4 +73,10 @@ public class JdbcQueryMethod extends QueryMethod {
 		return AnnotationUtils.findAnnotation(method, Modifying.class) != null;
 	}
 
+	@SuppressWarnings("unchecked")
+	private <T> T getMergedAnnotationAttribute(String attribute) {
+
+		Query queryAnnotation = AnnotatedElementUtils.findMergedAnnotation(method, Query.class);
+		return (T) AnnotationUtils.getValue(queryAnnotation, attribute);
+	}
 }

src/main/java/org/springframework/data/jdbc/repository/support/JdbcRepositoryQuery.java

@@ -15,11 +15,13 @@
  */
 package org.springframework.data.jdbc.repository.support;
 
+import org.springframework.beans.BeanUtils;
 import org.springframework.dao.EmptyResultDataAccessException;
 import org.springframework.data.jdbc.mapping.model.JdbcMappingContext;
 import org.springframework.data.repository.query.RepositoryQuery;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
+import org.springframework.util.StringUtils;
 
 /**
  * A query to be executed based on a repository method, it's annotated SQL query and the arguments provided to the
@@ -36,29 +38,34 @@ class JdbcRepositoryQuery implements RepositoryQuery {
 	private final JdbcMappingContext context;
 	private final RowMapper<?> rowMapper;
 
-	JdbcRepositoryQuery(JdbcQueryMethod queryMethod, JdbcMappingContext context, RowMapper rowMapper) {
+	JdbcRepositoryQuery(JdbcQueryMethod queryMethod, JdbcMappingContext context, RowMapper defaultRowMapper) {
 
 		this.queryMethod = queryMethod;
 		this.context = context;
-		this.rowMapper = rowMapper;
+		this.rowMapper = createRowMapper(queryMethod, defaultRowMapper);
+	}
+
+	private static RowMapper<?> createRowMapper(JdbcQueryMethod queryMethod, RowMapper defaultRowMapper) {
+
+		Class<?> rowMapperClass = queryMethod.getRowMapperClass();
+
+		return rowMapperClass == null || rowMapperClass == RowMapper.class ? defaultRowMapper
+				: (RowMapper<?>) BeanUtils.instantiateClass(rowMapperClass);
 	}
 
 	@Override
 	public Object execute(Object[] objects) {
 
-		String query = queryMethod.getAnnotatedQuery();
+		String query = determineQuery();
 
-		MapSqlParameterSource parameters = new MapSqlParameterSource();
-		queryMethod.getParameters().getBindableParameters().forEach(p -> {
-
-			String parameterName = p.getName().orElseThrow(() -> new IllegalStateException(PARAMETER_NEEDS_TO_BE_NAMED));
-			parameters.addValue(parameterName, objects[p.getIndex()]);
-		});
+		MapSqlParameterSource parameters = bindParameters(objects);
 
 		if (queryMethod.isModifyingQuery()) {
+
 			int updatedCount = context.getTemplate().update(query, parameters);
 			Class<?> returnedObjectType = queryMethod.getReturnedObjectType();
-			return (returnedObjectType == boolean.class || returnedObjectType == Boolean.class) ? updatedCount != 0 : updatedCount;
+			return (returnedObjectType == boolean.class || returnedObjectType == Boolean.class) ? updatedCount != 0
+					: updatedCount;
 		}
 
 		if (queryMethod.isCollectionQuery() || queryMethod.isStreamQuery()) {
@@ -76,4 +83,25 @@ class JdbcRepositoryQuery implements RepositoryQuery {
 	public JdbcQueryMethod getQueryMethod() {
 		return queryMethod;
 	}
+
+	private String determineQuery() {
+
+		String query = queryMethod.getAnnotatedQuery();
+
+		if (StringUtils.isEmpty(query)) {
+			throw new IllegalStateException(String.format("No query specified on %s", queryMethod.getName()));
+		}
+		return query;
+	}
+
+	private MapSqlParameterSource bindParameters(Object[] objects) {
+
+		MapSqlParameterSource parameters = new MapSqlParameterSource();
+		queryMethod.getParameters().getBindableParameters().forEach(p -> {
+
+			String parameterName = p.getName().orElseThrow(() -> new IllegalStateException(PARAMETER_NEEDS_TO_BE_NAMED));
+			parameters.addValue(parameterName, objects[p.getIndex()]);
+		});
+		return parameters;
+	}
 }